Telephone muffler and voice control



. b 7 R. FRON TELEPHONE MUFFLER AND YOICE CONTROL v Filed Jan. 28, 1926 TJEL JL- INVENTOR 130116;? E'on BY ATTORNEY mum FBON, or Kansas Patented Feb;1122,1927.

CITY, MISSOURI, ASSIGNOR 'ro Jot-EN 'r. eosenovn, or

KANSAS, crrY, MISSOURI. I

PATENT orrlcs.

TELEPHONE MUFFLER AND VOICE CONTROL.

Application filed January 28, 1826. Serial No. 84,355.

' Theinvention generally relates to telephone attachments which have for their purpose to provide for more distinct and private transmission of telephonic conver- 6 sationsl 1f v *In'its moredetailed nature the invention seeks to provide a simple and inexpensively manufactured appliance which may be quickly and conveniently attached to a conventional telephone transmitter and which 'isdesigned to closely fit the face about the i mouth o f'one talking over the-telephone and'to so-receive the sound vibrations set f u p-by the conversation carried on that the words spoken will be clearly and distinctly audible to one at the receiving end of the line but practically inaudible to one closely 1 adjacent the transmitting end of the instrumentl In addition to providing for the '20 .Inufiling'of the sound vibrations to render v 'themtfinaudible to persons present in the I'room from which the message is transmitted, and thus facilitating transmission of secret 7 or private conversations, means is also profvided whereby the volume of the sound [transmitted may be adjusted to meet demandsoccasioned by each particular telephonic connection.

- *With the above and other objects in view 130, that "will" hereinafter appear the invention further re'sides in the novel details of con struct'ion, combinationand arrangement of parts; all ofwhich will be first fully described then be particularly pointed out in the appended claims,- reference beinghad to 'the accom panying drawing, in which fFigure'Iis a central horizontal section v'ofeniy improved muilier and control attachment, parts. of a telephonetransmitter being Q 'sh0wn in dotted lines." V

Figure'Q is a cross section taken on the fliilQQQ on'lFigure 1. I

In :the drawing in which like numerals of referenceindicate like parts in all of the figures, l representsthe base, 2 the standard, 4 :3 the transmitter*head," and 4: the mouth Jlpiece of mitten;

a conventional telephone trans- V The parts thus' far described are 'conventionaland are illustrated merely to 350' show the application of the invention and form nopartthereof, per se.

In carrying out the principles of my invention I provide a cylindrlcal casing 5 open at its rear end and of a diameter slightcured on the casing as at 7 and adapted to abut the front face of the transmitter head to position the attachment, and a plurality of set'screws 8 which take through the ringand-flange connections? to the rear of the ring 6 and engagc the rear curved part of the transmitter head 3 to secure the device to position in the manner shown in Figure 1 of the drawing. 1

The front end of the casing 5 is closed by the wall 9 which has a central aperture 1-0 in which is secured the mouthpiece 11 shaped as at 12 to snugly fit the face about the mouth of a talker to direct all sound vibrations into the casing and prevent escape of any part thereof directly into the room.

A mufiler cylinder 13isfiange-secured as at 14 between the ring 6 and the end of the casing 5 so as to be mounted within and in spaced relation to the wall of the casing 5. The cylinder 13 is perforated as at 15 to provide for communication between the chamber within and that surrounding the said cylinder, and thefront wall 16 thereof is so spaced from the flange mounting, and the cylindrical wall so proportioned, that it freely cups over the mouthpiece l when the attachment is mounted as illustrated in Figure 1 of the drawing. It will also be observed that the central aperture of the ring 6 is sufficiently large to freely pass The rear wall 18 of thedepression 17 has sound vibration passageslQformed therein and acontrol disk 20, similarly apertured as at 21, is rotatably mounted as at 22 upon the said rear wall 18 so that when the said disk is rotated the apertures or passages 19 and 21 will be brought into or out of register to control or cut off direct passage of sound vibrations into and through the mouthpiece 4 to the diaphragm in the transmitterhead To provide for the necessary movement of the disk 20 it is provided with an eye through Which is inserted the crank end 24: of the rotatable control rod 25 which passes through the casing 5 at 26, the extended end being provided with a knurled head 27 to facilitate the making of the adjustments.

In use the mouth is placed close against the shaped edge 12 of the mouthpiece 11 and the conversation proceeded with. All sound vibrations are effectively directed into the attachment and through the same in to the mouthpiece of the telephone instrument. In'this manner conversation may be carried on unheard by persons in the room from which the message is being transmitted.

The voices of different people carry in varying degree and this, considered also with the variations in sense of hearing of different individuals and the variations in telephonic connections made at various times, makes very desirable the use of the sound devices 13, 15, 1827.

c When the apertures 19 and 21 are in full register the sound vibrations are permitted to pass, in full volume, directly into the transmitter head mouthpiece 4C. By varying the degree of opening through the wall 18 and disk 20 the volume and direct passage of the sound vibrations may be varied and when the passages are wholly closed the sound vibrations will be caused to take a tortuous passage around the cylinder 13, through its apertures 15 into the space surrounding the mouthpiece 4t and into the annular space surrounding the depressions 1'7 and thereby considerably mufiied or deadened before reaching the diaphragm within the transmitter head 3.

The casing 5 may be provided with one or more apertures 28 providing communi cation between the interior of the casing and atmosphere. Thus air is permitted to enter and be expelled'through the aperture or apertures so that respiration during telephone conversation is not interfered with and all back pressures prevented.

A sound deadening ring 29 of felt or similar material may be interposed between the ring 6 and the transmitter head 3 if desired.

By the use of my improved attachment it is possible to transmit secret or private messages inaudible. to persons the roon'i in which the messages are being t ismitted, also, to so control the sound v brations to attain a maximum of efficiency in trans mitting the messages under varying cond tions due to variations in volume of voice of the transmitting person, of the sense of hearing of the receiving person, and in the telephonic connections made at the central exchange ofiice.

From the foregoing description, taken in connection with the accompanyin drawing, it is thought that the novel details of construction, the manner of use, and the advantages of the invention will be readily apparent to those skilled in the art to which it relates.

What I claim is:

1. A device of the class described comprising a casing adapted to fit over the transmitter mouthpiece of a telephone instrument, a mouthpiece communicating into the interior of the casing, a perforated baflie cylinder-carried by the casing in spaced relation therein and surrounding the transmitter mouthpiece when the device is mounted for use, a front wall carried by the cylinder in spaced relation in advance of the transmitter mouthpiece when the device is mounted for use, said wall having a central depression adapted to project back into said transmitter mouthpiece a distance in spaced relation.

2. A device of the class described comprising a casing adapted to fit over the transmitter mouthpiece of a telephone instrument, a mouthpiece communicating into the interior of the casing and shaped to fit the face about the mouth of a user, and variable means for controlling the passage of sound vibrations through the easing into the transn'iittcr mouthpiece of the telephone instrument over which the casing has been fitted, said means including an apertured wall carried by the casing and extended a distance back into the transmitter mouthpiece and an apertured disk movable relatively upon the said wall, and a rod extended outside the casing to one side of said second mentioned mouthpiece for effecting movement of said disk. I

3. The combination with a telephone transmitter head and its 'mouthpiece, of a cas ng adapted to snugly fit over said head. an abutment ring secured in the casing and adapted to abut said head, set screws threaded through the casing wall beyond the ring and adapted to impinge said head to secure the casing to position, a cylinder secured to the ring in spaced relation inside the casing and adapted to surround said transmitter head mouthpiece and having its cylindrical wall perforated, said cylinder having its front wall provided with a central depression adapted to extend into said transmitter head mouthpiece and having sound vibration admitting passages.

4. The combination with a telephone transmitter head and its mouthpiece, of a casing adapted to snugly fit over said head, an abutment ring secured in the casing and adapted to abut said head, set screws threaded through the casing Wall beyond the ring and adapted to impinge saidhead to secure the. casing to position, a cylinder secured --to the ring in spaced relation inside the casing and'adapted to surround said transmitter head mouthpiece and having its cylindrical Wall perforated, said cylinder having its front wall provided with a central 

